I think there's a difference, however, between offering a cafeteria, and taking meals together as a team/family... Is this the motivation for Google/Facebook and some of the others who do this? b/c I was under the impression that the perk was offered more as a convenience than as a fundamental part of team cohesiveness...

Ever since my first startup laid me off, I hate it when CEOs compare a startup to a family. For one thing, families don't jettison 30% of their members every so often. Also, startups are very often places that PREVENT you from spending time with your actual family. And finally, I like to get out of the office and see new people and new things during lunch rather than same old, same old.